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<b>let </b><font color="Maroon" title="c1">X</font> be  non <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>  <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>let </b><font color="Maroon" title="c2">f</font> be   <a href="funct_2.html#NM1" title="FUNCT_2:NM.1">Function</a> of <span class="p1"><a href="zfmisc_1.html#K2" title="ZFMISC_1:func.2">[:</a><span class="default"><font color="Maroon" title="c1">X</font>,<font color="Maroon" title="c1">X</font></span><a href="zfmisc_1.html#K2" title="ZFMISC_1:func.2">:]</a></span>, <a href="numbers.html#K1" title="NUMBERS:func.1">REAL</a> ;<br/>



<b>assume </b><a NAME="E1:11"/><i><font color="Green" title="E11">A1</font></i>: 
<font color="Maroon" title="c2">f</font> <a href="nagata_1.html#R1" title="NAGATA_1:pred.1">is_a_pseudometric_of</a> <font color="Maroon" title="c1">X</font>
 ;<br/>

<b>let </b><font color="Maroon" title="c3">A</font> be   <a href="subset_1.html#NM2" title="SUBSET_1:NM.2">Subset</a> of <font color="Maroon" title="c1">X</font>;<br/><b>let </b><font color="Maroon" title="c4">x</font> be    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Maroon" title="c1">X</font>;<br/>



<b>assume </b><a NAME="E2:11"/><i><font color="Green" title="E12">A2</font></i>: 
<font color="Maroon" title="c4">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c3">A</font>
 ;<br/>

<b>then reconsider </b><font color="Maroon" title="c5">A</font> = <font color="Maroon" title="c3">A</font> as  non <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a> <a href="subset_1.html#NM2" title="SUBSET_1:NM.2">Subset</a> of <font color="Maroon" title="c1">X</font> ;<br/>
<a NAME="E4:11"/>
<font color="Maroon" title="c2">f</font> is <a href="metric_1.html#V2" title="METRIC_1:attr.2">Reflexive</a>
 
<b>by </b><i><a class="txt" href="nagata_2.html#E1:11"><i><font color="Green" title="E11">A1</font></i></a>, <a class="ref" href="nagata_1.html#D10" title="NAGATA_1:def.10">NAGATA_1:def 10</a></i>;<br/>
<a NAME="E5:11"/><b>then </b>
( <font color="Maroon" title="c2">f</font> <a href="metric_1.html#K1" title="METRIC_1:func.1">.</a> <font color="Maroon" title="c4">x</font>,<font color="Maroon" title="c4">x</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  &amp; <font color="Maroon" title="c1">X</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="relset_1.html#K4" title="RELSET_1:func.4">dom</a> <span class="p1">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> )
 
<b>by </b><i><a class="ref" href="funct_2.html#D1" title="FUNCT_2:def.1">FUNCT_2:def 1</a>, <a class="ref" href="metric_1.html#D3" title="METRIC_1:def.3">METRIC_1:def 3</a></i>;<br/>
<a NAME="E6:11"/><b>then </b>
( <span class="p1">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c4">x</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  &amp; <font color="Maroon" title="c4">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="relset_1.html#K4" title="RELSET_1:func.4">dom</a> <span class="p1">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> )
 
<b>by </b><i><a class="ref" href="nagata_2.html#D2" target="_self" title="NAGATA_2:def.2">Def2</a></i>;<br/>
<a NAME="E7:11"/><b>then </b>
(  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> <a href="relset_1.html#K10" title="RELSET_1:func.10">.:</a> <font color="Maroon" title="c5">A</font> &amp; not <span class="p1">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> <a href="relset_1.html#K10" title="RELSET_1:func.10">.:</a> <font color="Maroon" title="c5">A</font> is <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a> &amp; <span class="p1">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> <a href="relset_1.html#K10" title="RELSET_1:func.10">.:</a> <font color="Maroon" title="c5">A</font> is <a href="seq_4.html#V2" title="SEQ_4:attr.2">bounded_below</a> )
 
<b>by </b><i><a class="txt" href="nagata_2.html#E1:11"><i><font color="Green" title="E11">A1</font></i></a>, <a class="txt" href="nagata_2.html#E2:11"><i><font color="Green" title="E12">A2</font></i></a>, <a class="txt" href="nagata_2.html#E8"><i><font color="Green" title="E8">Lm1</font></i></a>, <a class="ref" href="funct_1.html#D12" title="FUNCT_1:def.12">FUNCT_1:def 12</a></i>;<br/>
<a NAME="E8:11"/><b>then </b>
(  <a href="pscomp_1.html#K3" title="PSCOMP_1:func.3">inf</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="nagata_2.html#K3" title="NAGATA_2:func.3">dist</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c4">x</font></span>)</span> <a href="relset_1.html#K10" title="RELSET_1:func.10">.:</a> <font color="Maroon" title="c5">A</font></span>)</span> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  &amp; <font color="Maroon" title="c2">f</font> is <a href="seq_2.html#V2" title="SEQ_2:attr.2">bounded_below</a> )
 
<b>by </b><i><a class="txt" href="nagata_2.html#E1:11"><i><font color="Green" title="E11">A1</font></i></a>, <a class="txt" href="nagata_2.html#E8"><i><font color="Green" title="E8">Lm1</font></i></a>, <a class="ref" href="seq_4.html#D5" title="SEQ_4:def.5">SEQ_4:def 5</a></i>;<br/>
<a NAME="E9:11"/><b>then </b>
( <span class="p1">(<span class="default"><a href="nagata_2.html#K4" title="NAGATA_2:func.4">inf</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c5">A</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c4">x</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  &amp; <span class="p1">(<span class="default"><a href="nagata_2.html#K4" title="NAGATA_2:func.4">inf</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c5">A</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c4">x</font> <a href="xxreal_0.html#NR2" title="XXREAL_0:NR.2">&gt;=</a>  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  )
 
<b>by </b><i><a class="txt" href="nagata_2.html#E1:11"><i><font color="Green" title="E11">A1</font></i></a>, <a class="ref" href="nagata_2.html#D3" target="_self" title="NAGATA_2:def.3">Def3</a>, <a class="ref" href="nagata_2.html#T5" target="_self" title="NAGATA_2:th.5">Th5</a></i>;<br/>
<b>hence </b><a NAME="E10:11"/>
<span class="p1">(<span class="default"><a href="nagata_2.html#K4" title="NAGATA_2:func.4">inf</a> <font color="Maroon" title="c2">f</font>,<font color="Maroon" title="c3">A</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c4">x</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="numbers.html#K6" title="NUMBERS:func.6">0</a> 
 ;<br/>


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